In recent years, systems that use personal authentication techniques using biological information have been in widespread use. As an example of such personal authentication techniques, there is a face authentication technique for authenticating an individual on the basis of, for example, a person's face image.
Patent Document 1 discloses a cellular phone that calculates the degree of suitability by collating a face image of a person to be authenticated which is acquired through an imaging unit with face feature information included in a storage unit, compares the calculated degree of suitability with a threshold determined on the basis of position information acquired by a position information acquisition unit, and determines the success or failure of face authentication.